Core for electrical apparatus



C. E. LEE. i CORE FOR LECTRICAL'APPARAT'US.

APPLICATION FILED OCT. 18| 1920.

1,380,983. .PanteaJunw/i1921,

my H Ammmmy lUN-VIED @STATE-s PATENT OFFICE.

CORLISS E. LEE, OI?l PITTSFIELD, MSSACHUSE'T ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

CORE FOR ELECTRICAL APPARATUS.

` To all who/mit may concern:

Be it known that I, CoRLIss E. LEE, a-

` citizen ofv the United States, residing at Pittsfield, in the county .of Berkshire, State of Massachusetts, have invented certain new My invention relates to cores for electrical apparatus, such as transformers, some re- Y actances and the like andhas for its object an improved arrangement of parts which is economical and' readily manufactured. In electrical apparatus having magnetic cores, and particularly in transformers and the like, it is desirable to construct the cores with as few `joints as possible in order to reduce the reluctance of the magnetic ycircuit and thereby reduce the losses and exciting current. The use of L-'shaped elements or punchings is well adapted to this purpose in the construction of rectangularly shaped cores; arrangements of Ls hereto- I fore proposed for accomplishing this end being shown in the U. S. patent to Thomson No. 528,188.

In rectangular three legged cores adapted for three phase core-type transformer and for certain single-phase shell type transformers, the type of L-shaped elements which were in general previously used have on the average over three joints per path traversed by the magnetic flux of the group of magnetic circuits involved.

In the practice of myinvention I employ only Ls inthe construction of core laminations' with consequent savings in the sheet material from which they are cut;'the Lsthemselves being proportioned and arranged in the novel manner hereinafter pointed out which lreduces the number of joints to anl average of approximately2-6 therebydecreasing the power losses and exciting current to substantially a minimum.

For a more complete understanding of the nature and objects of my invention, refi f erence should be had to the following de j tailed description taken in connection with structed in accordance with my invention;.

while Figs. 2 and 3 show arrangements of Ls to form core laminatioiis which are employed inthe practice of my invention.4

Specification of Letters PateiiJt.

Patented June 7, 1921.

Application led October 18, 1920. Serial No. 417,714.

Referring now to the drawing, 10 denotes a three legged core having high and low voltage windings 11 and 12von each of the respective legs.

The core carrying these windings is assembled from Ls which are inserted in the windings, the latter being wound and first arranged; the arrangement of Ls in the assembly shown in Fig. 1 being more clearly shown in Fig. 2.

Here two Ls 15 and 16, which are identical in size and shape, are oined with and butted against a larger L 17 to form a lamination. The L-shaped lamination 15 forms one leg and a portion of one yoke, as denoted at 18. The same is true of L-shaped punching 16, which has a portion 19 coacting with the portion 18 to complete the lower yoke. The L 17 forms the third leg and the other yoke.

The average number of joints inthe group of paths traversed by the magnetic liux for the circuits involved will be seen to be very approximately 2.6 from the following con- Vsiderations:l The flux from the winding about the leg of the' L denoted 15 follows the paths P, and P2. The path P, crosses `a joint at 21, one at 22, and a third at 23,71. e.,

it has three joints. The path P2 crosses a joint at 21, one at 22, and another at 24, and -likewise has three joints. Y

winding about the leg of L 17 follows paths P3 and P2 which have two and three joints respectively. The average number of joints of these six paths ltaken collectively is very approximately 2.6.

It will of course be understood that each alternate lamination or group of laminations of the type shownV in Fig. 2 has the Ls -composing it reversely .disposed in order to break joints. This, however, is an old practice welly understood in the art, consequently further explanation is deemed unnecessary.

In Fig. 3' I haveshown a lamination simi# lar to that-shown in Fig. 2 but composed ofthree different sized Ls. The L shown at 30 is 'a large L adapted to provide one leg.

ate sized L 35 provides the third leg 36 and the balance of the upper yoke portion 37. This arrangement permits the nse'of a vertical joint at 38 instead of a horizontal one; Which vertical arrangement has the advanf tage of providingr a joint at a point in the magnetic circuit which has a lower iiuX density than where the horizontal joint is illustrative and that l do not `mean to be limited thereby to the exact details shown nor restricted in the' choice of recognized equivalents except as deiined in my claims o hereunto appended.

What claim as new and desire to secure by Letters Patent of the United States, is

l. A core for electrical apparatus comprising vyoke members and n legs, assembled solely from L-shaped elements, each lamie nation in the core having one element arranged to form one leg and one yoke, and

n-l other elements' each arranged to form another leg and part of a second yoke.

2. A core for transformers and the like, comprising two yoke members and three legs, assembled solely from Lshaped punchings; each lamination in the core having one punching arr'anged to form oneleg and one yoke, and tWo other punchings each arranged to form another leg and a portion of the second yoke. l

ln witness whereof, l have hereunto set my hand this fourteenth day of October, i920.

ooRLrss E. LEE. 

